The Maeslantkering

The Netherlands is located in a low-lying delta, where large rivers such as the Rhine and IJssel run into the sea. The history of the Netherlands has been determined by the struggle against water. The Flood Disaster in 1953 was a rude awakening for the country. The fatal combination of a north-westerly storm and spring tide resulted in the inundation of large parts of the provinces of Zeeland and South Holland. Over 1800 people died and the flood caused enormous damage to houses and property. Only one conclusion could be drawn: the country was not safe. Measures to prevent a repetition of the disaster were put forward in the form of the Delta Plan. The dykes in Zeeland and South Holland had to be raised to delta level: they had to be capable of withstanding storm surges as much as one and a half metres higher than those during the notorious storm in 1953.

An alternative to dike reinforcements in South Holland is a storm surge barrier. This option turns out to be the most attractive in terms of cost, environmental effects and safety. Furthermore a storm surge barrier can be built more rapidly than dike reinforcements. The environmental impact statement is completed and approved within six months. In 1987 the Dutch government decides that the New Waterway Storm surge barrier should be constructed. The Dutch government asked building contractors to produce a design for the storm surge barrier. Six designs were submitted. The Bouwkombinatie Maeslant Kering (BMK) submitted the winning design.

If a water level of 3.00 metres above NAP is anticipated for Rotterdam the Storm Surge Barrier in the New Waterway has to be closed. In these circumstances the Storm Surge Barrier computer - the Command and Support System (Dutch acronym BOS) instructs the Control System (BES) to shut the barrier. The BES implements the BOS's commands.

In the event of a storm tide, the docks are filled with water, so that the hollow gates start to float and can be turned into the New Waterway. Once the gates meet, the cavities are filled with water and the gates sink to the bottom, thus sealing off the 360 metre-wide opening. After the high water has passed the gates are pumped out and the structure begins to float again. Once it is certain that the next high water will not be another abnormally high one, the two gates are returned to their docks.

When the New Waterway is sealed off it is no longer possible for shipping to pass. The storm-surge barrier will only be closed in extremely bad weather – in probability once every ten years. A test closure will probably be conducted once a year in order to check the equipment. This will be done when there is little shipping. With the rise in sea levels the storm-surge barrier will need to close more frequently in 50 years time, namely once every five years.

Here you can see the Maeslantkering!

1.Construction of 1-meter high dyke on the Rozenburg peninsula from the southern abutment of the New Waterway Storm Surge Barrier towards Rozenburg.

2.Reinforcement of the south-western portion of the water defense system around Rozenburg. Elevation of existing dyke. The Europort Barrier then runs from Rozenburg across the Botlekweg. At the Welplaatweg the barrier joins up with the A15 via the eastern slope.

3.The route then runs to the Hartel Bridge. In the vicinity of the bridge a moveable storm surge barrier - the Hartel Barrier - is built in the Hartel Canal. The Hartel Locks are fitted with new lock- gates and new operating equipment and the outer head is elevated. The number of temporary mooring sites for vessels is increased. The Hartel Barrier is also fitted with a guard in order to protect the barrier from large and heavy floating debris, such as empty containers. In addition a new control building is added to operate the barrier and the lock.

4.The Brielse Maas Dyke has to be elevated by 2.5-3 meters between the Hartel Barrier and the Suurhoff Bridge. Pipeline crossings in the Brielse Maas Dyke are modified. Bank and toe protection are extended both upwards and downwards.

Photo’s

Now the barriers are open and at the next picture they are closed

The trusses, each 237 metres in length, are a prominent visual part of the Storm Surge Barrier. Their function is to transmit directly to the ball-joint the loads exerted on the retaining walls in the closure process. During closure the truss will ride up and by approximately 40 centimetres into a camber, levelling out again when the load eases.

Dimensions:

Each arm consists of two separate open- frame girders joining up at the ball- joint.

Length:	237 meters
Maximum height:	20 meters
Main girder cross-section:	1.80 meters
Main girder wall-thickness:	60 - 90 mm
Diagonals cross-section:	60 - 80 mm
Diagonals wall-thickness:	12 - 30 cm
Maximum compressive force:	300 MN
Tensile force (given negative head):	50 MN
Connection with hinge:	- end-diagonal
	- tailpiece
Camber:	8 cm

The barriers were constructed with a camber of 500 mm. After removal of the supports a camber of 80 mm remained.